1. Field of the Invention
The present invention relates to systems and methods for processing brine shrimp eggs. More specifically, the present invention relates to an apparatus and method for drying, cleaning, and disinfecting brine shrimp eggs to provide a highly viable end product.
2. Description of Related Art
Brine shrimp are a nutritious food source for fish and shrimp larvae. Brine shrimp eggs, or xe2x80x9ccysts,xe2x80x9d are harvested from the surface of a body of water with a high saline content. The eggs can then be dried and stored for lengthy periods of time before hatching; consequently, they can be stockpiled to maintain a population of sea life during times when there is little natural food available.
When harvested, the eggs are invariably gathered together with egg shells, dead brine shrimp, sand, debris, other sea life, and the like. Such material may generally be referred to as xe2x80x9cdetritus.xe2x80x9d Additionally, the eggs contain significant quantities of water, which adheres to the outsides of the eggs and is also absorbed by the shells. Hence, the eggs are not only wet, but are also internally saturated with moisture. The water and detritus add significantly to the weight and volume of the brine shrimp eggs.
Furthermore, in the presence of water, the eggs will eventually commence hatching, thereby losing their ability to hatch upon re-hydration. Consequently, the brine shrimp eggs must be dried, internally and externally, and separated from detritus prior to shipping. Additionally, in certain climates, the brine shrimp eggs may tend to carry bacteria that are potentially harmful to the eggs, to the hatched brine shrimp, to the sea life that consumes the brine shrimp, or to the ultimate consumer of the sea life. Thus, it may also be beneficial to disinfect the eggs prior to shipment.
According to known methods, rotating drums, conveyer systems, moving screens, and the like have been used to dry brine shrimp eggs for packaging. Heated air is often blown over the brine shrimp eggs to effect drying. Mechanical devices such as sieves have been used to separate the eggs from detritus.
Unfortunately, such methods are inadequate for a number of reasons. For example, many such methods require an excessive length of time, such as seven or eight hours, to dry and sort a single batch of brine shrimp. The time required tends to cause some of the cysts to begin the hatching process in response to the heat and moisture. Hence, some of the cysts will no longer be viable by the time the drying operation is complete.
In addition, the mechanisms employed often provide a poor separation of the cysts from the accompanying detritus; consequently, the viable content of the final product is further reduced. Additionally, many known methods and devices disinfect the brine shrimp eggs through the use of somewhat destructive chemical methods, such as chlorine rinsing. Other known brine shrimp processing schemes include no disinfecting method, thereby risking exposure of the eggs to harmful bacteria.
Accordingly, a need exists for a brine shrimp egg processing apparatus and method that effectively dries eggs, internally and externally, within a comparatively short time frame. Furthermore, a need exists for an apparatus and method for effectively separating detritus from viable cysts. Yet further, a need exists for an apparatus and method for disinfecting the cysts without subjecting them to potentially damaging chemicals.
The apparatus and method of the present invention have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available brine shrimp processing systems. Thus, it is an overall objective of the present invention to provide a brine shrimp egg processing apparatus and method that remedies the shortcomings of the prior art. Such an apparatus and method may more rapidly dry the brine shrimp eggs, while using effective and non-destructive methods to disinfect the eggs and separate them from detritus.
To achieve the foregoing objective, and in accordance with the invention as embodied and broadly described herein in the preferred embodiment, an enhanced brine shrimp egg processing apparatus is provided. The processing apparatus may have a blower that provides a flow of pressurized air, a furnace that decreases the relative humidity of the air, a screening device that separates detritus from viable cysts, a containment vessel that forms an air column to support the cysts, and an extractor that removes and sorts the detritus and/or brine shrimp eggs.
The blower may simply receive air from the atmosphere, and may pressurize the air at a desired level. A variable damper, for example, may be used to adjust the pressure and/or flow rate of the air from the blower. The furnace may heat the air to a temperature warm enough to dry the eggs, yet not so warm as to damage the eggs or initiate hatching. The air temperature may be monitored after leaving the furnace through the use of a thermostat; the thermostat may provide feedback control for the furnace to keep the air at the desired temperature.
The air may then enter the screening device, which may have a plenum chamber that receives the air. The air may move upward from the plenum chamber through a vibrating screen with a mesh size just small enough to retain the viable cysts, to reach a separation chamber. Brine shrimp eggs may be carried upward and out of the separation chamber by the air. Detritus, such as shell fragments and the like, may fall through the screen, through the plenum chamber, and into a detritus chamber. Some detritus may also be caught in the airflow with the cysts. A discharge chute may be coupled to the separation chamber to channel viable cysts into a collection container after the apparatus has been deactivated.
The air, with entrained cysts and detritus, moves through a coupling to reach the containment vessel. The containment vessel has a loading chute through which the brine shrimp eggs can be loaded into the apparatus. Furthermore, the containment vessel may have a first section in which the air moves at a comparatively high velocity, and a second section in which the air moves more slowly. In one embodiment, the first section may take the form of a lower, narrow section, and the second section may be an upper, wide section. A flare may be disposed between the two sections. The velocity of the air drops substantially as the air moves through the flare and into the wide section. Hence, the heavier, viable cysts remain within the narrow section, while the lighter detritus is carried into the wide section.
Ultraviolet lights may be included within the narrow section to subject the cysts to ultraviolet radiation. The ultraviolet radiation destroys harmful microbes present on the shells of the cysts. One or more video cameras may be disposed on the wide section and angled so that the field of view of the camera is directed downward, into the collection vessel. Lights may also be used to illuminate the interior of the collection vessel so that the brine shrimp eggs and detritus can be effectively viewed by the camera. The camera may be connected to a display at a remote terminal, from which an operator may monitor and control the apparatus. Other sensors, such as pressure sensors, air velocity sensors, moisture sensors, and the like may additionally or alternatively be used.
The wide section may have a screen at the top, through which air, but not viable cysts, is able to exit the apparatus. Furthermore, the extractor may be coupled to the wide section by a conduit. The extractor may have a blower that draws air and entrained material from the wide section. The extractor may draw the air and entrained material into a receiving chamber, below which a conical chamber is disposed. The conical chamber may act as a cyclone separator, from which heavier particles drop, while lighter particles remain entrained in the airflow. Hence, comparatively heavy, viable cysts may drop into one collection container, while the lighter detritus drops into another.
According to one alternative embodiment, the first and second sections have the same cross sectional area. Again, the second section may be disposed on top of the first section. The airflow velocity differential may be provided by a plurality of vents that permit air to escape from the containment vessel after moving through the first section. The vents may be covered with screens that have a mesh size too small to permit the brine shrimp eggs to escape between the first and second sections. Thus, a smaller flow rate of air moves through the second section, and the velocity of the air is lower in the second section than in the first section. Consequently, as with the previous embodiment, brine shrimp eggs are concentrated within the first section, while detritus tends to rise into the second section.
Through the use of the brine shrimp processing apparatus and method of the present invention, brine shrimp eggs may be gently and rapidly dried through entrainment in an airflow. Furthermore, the brine shrimp eggs may be effectively separated from impurities such as shell fragments, sand particles, and other detritus. The brine shrimp eggs may also be disinfected in a nondestructive, complete manner to protect them against harmful bacteria.
These and other features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.